The rise around first class is authentic (4)
I believe the answer is:
echt
'authentic' is the definition.
(I've seen this before)
'the rise around first class' is the wordplay.
'rise' says the letters should be written backwards.
'around' means one lot of letters goes inside another.
'first class' becomes 'c' (1st letter of 'class').
'the' back-to-front is 'eht'.
'eht' placed around 'c' is 'ECHT'.
'is' is the link.
(Other definitions for echt that I've seen before include "German's real" , "Genuine (Ger.)" , "True" , "Genuine (German)" , "Genuine - authentic" .)